This invention relates to novel antibacterial compounds and to the treatment of bacterial infections in animals in need of such treatment. The antibiotics LL-E19020 .alpha. and .beta. are disclosed and claimed by physical/chemical characteristics in U.S. Pat. No. 4,705,688, the contents of which are hereby incorporated by reference. These antibiotics, derived from the microorganism streptomyces lydicus subspecies tanzanius NRRL 18036, are active as antibacterial agents. They are also growth promoters, anti-protozoan agents, and anthelmintic agents.
Another complex of antibiotics named Phenelfamycins has been disclosed by Abbott Laboratories, Abbott Park, Ill. at the 27th Interscience Conference on Antimicrobial Agents and Chemotherapy, New York, NY in October, 1987.
The structures of LL-E19020 .alpha. and .beta. are reproduced below:
__________________________________________________________________________ ##STR1## R.sub.2 R.sub.1 __________________________________________________________________________ LL-E19020.alpha. H ##STR2## LL-E19020.beta. ##STR3## H __________________________________________________________________________
An object of the present invention is to provide chemical derivatives of the antibiotics LL-E19020 .alpha. and LL-E19020 .beta. which also have activity as antibacterial agents.